Last year, I bought this old gun at a yard sale with the intentions of parting it out. But, I now have other plans for it and do need some help. It is missing the extractor and at least one screw that would be inserted in the top of the tang and it will not lock up. I am wondering if the lock up issue is because the extractor is missing - something is failing to trip the opening lever back to center. The parts all match as far as serial numbers go so what I have is right but I do need some more. This brings me to another question, are there any good books available for working on double barrel shotguns? I have a couple more that need some help as well. Also, if anybody knows who made this gun I would appreciate that info as well.